Discovery and MID Servers When determining if you need multiple MID Servers to discover the configuration items in your network efficiently, the following factors must be considered: WAN deployment: When determining where to deploy MID Servers in a WAN, consider the bandwidth available between your local area networks. In most cases, the best practice is to install a MID Server on each LAN to probe devices locally, rather than deploying MID Servers that must probe devices across slow WAN connections. An alternative to this type of deployment is to install MID Servers that probe other LANs via VPN connections that take advantage of fast Internet connections. If the bandwidth of your WAN connections is comparable to that of your Internet connection, then there is no performance impact in running MID Server probes across WAN connections. DMZ: Your network policy might require you to install one or more MID Servers in your DMZ to probe the devices there. This is common in networks that tightly regulate the ports that are opened on the inside firewall. High capacity: Deploy multiple MID Servers where capacity is an issue, as when Discovery has to gather information about thousands of configuration items quickly. Security: If your security policy controls access to network devices (e.g. switches and routers) with an access control lists (ACL), it might be necessary to install one or more MID Servers on a machine in the network that is already on the ACL. Probe types: If you are conducting probes of different operating systems, your network policy might require a separate MID Server for each type of probe (e.g., one MID server for Windows WMI probes and another for SSH probes on UNIX).